Feature: --no-fading-openclose to partially simulate -F

-F hasn't being working for long. This commit adds a switch
--no-fading-openclose (and a configuration file option of the same name)
to simulate the behavior when only -F is enabled, which disables fading
when opening/closing windows, and makes -F an alias for -f.

compton.sample.conf

@@ -24,6 +24,7 @@ fading = true;
 # fade-delta = 30
 fade-in-step = 0.03
 fade-out-step = 0.03
+# no-fading-openclose = true;
 
 # Other
 mark-wmwin-focused = true;